Our discourse_public_exceptions middleware is designed to catch bubbled exceptions from lower in the stack, and then use `ApplicationController.rescue_with_handler` to render an appropriate error response.
When the request itself is invalid, we had an escape-hatch to skip re-dispatching the request to ApplicationController. However, it was possible to work around this by 'layering' the errors. For example, if you made a request which resulted in a 404, but **also** had some other invalidity, the escape hatch would not be triggered.
This commit ensures that these kind of 'layered' errors are properly handled, without logging warnings. It also adds detection for invalid JSON bodies and badly-formed multipart requests.
The user-facing behavior is unchanged. This commit simply prevents warnings being logged for invalid requests.
Currently, Discourse rate limits all incoming requests by the IP address they
originate from regardless of the user making the request. This can be
frustrating if there are multiple users using Discourse simultaneously while
sharing the same IP address (e.g. employees in an office).
This commit implements a new feature to make Discourse apply rate limits by
user id rather than IP address for users at or higher than the configured trust
level (1 is the default).
For example, let's say a Discourse instance is configured to allow 200 requests
per minute per IP address, and we have 10 users at trust level 4 using
Discourse simultaneously from the same IP address. Before this feature, the 10
users could only make a total of 200 requests per minute before they got rate
limited. But with the new feature, each user is allowed to make 200 requests
per minute because the rate limits are applied on user id rather than the IP
address.
The minimum trust level for applying user-id-based rate limits can be
configured by the `skip_per_ip_rate_limit_trust_level` global setting. The
default is 1, but it can be changed by either adding the
`DISCOURSE_SKIP_PER_IP_RATE_LIMIT_TRUST_LEVEL` environment variable with the
desired value to your `app.yml`, or changing the setting's value in the
`discourse.conf` file.
Requests made with API keys are still rate limited by IP address and the
relevant global settings that control API keys rate limits.
Before this commit, Discourse's auth cookie (`_t`) was simply a 32 characters
string that Discourse used to lookup the current user from the database and the
cookie contained no additional information about the user. However, we had to
change the cookie content in this commit so we could identify the user from the
cookie without making a database query before the rate limits logic and avoid
introducing a bottleneck on busy sites.
Besides the 32 characters auth token, the cookie now includes the user id,
trust level and the cookie's generation date, and we encrypt/sign the cookie to
prevent tampering.
Internal ticket number: t54739.
Allow admins to configure exceptions to our Rails rate limiter.
Configuration happens in the environment variables, and work with both
IPs and CIDR blocks.
Example:
```
env:
DISCOURSE_MAX_REQS_PER_IP_EXCEPTIONS: >-
14.15.16.32/27
216.148.1.2
```
Before this change, calling `StyleSheet::Manager.stylesheet_details`
for the first time resulted in multiple queries to the database. This is
because the code was modelled in a way where each `Theme` was loaded
from the database one at a time.
This PR restructures the code such that it allows us to load all the
theme records in a single query. It also allows us to eager load the
required associations upfront. In order to achieve this, I removed the
support of loading multiple themes per request. It was initially added
to support user selectable theme components but the feature was never
completed and abandoned because it wasn't a feature that we thought was
worth building.
Over the years we accrued many spelling mistakes in the code base.
This PR attempts to fix spelling mistakes and typos in all areas of the code that are extremely safe to change
- comments
- test descriptions
- other low risk areas
For sites with login_required set to true, counting anonymous pageviews is
confusing. Requests to /login and other pages would make it look like
anonymous users have access to site's content.
Fixes `Rack::Lint::LintError: a header value must be a String, but the value of 'Retry-After' is a Integer`. (see: 14a236b4f0/lib/rack/lint.rb (L676))
I found it when I got flooded by those warning a while back in a test-related accident 😉 (ember CLI tests were hitting a local rails server at a fast rate)
The regular expression to detect private IP addresses did not always detect them successfully.
Changed to use ruby's in-built IPAddr.new(ip_address).private? method instead
which does the same thing but covers all cases.
It returned a 429 error code with a 'Retry-After' header if a
RateLimiter::LimitExceeded was raised and unhandled, but the header was
missing if the request was limited in the 'RequestTracker' middleware.
`/srv/status` routes should not be cached at all. Also, we want to
decouple the route from Redis which `AnonymouseCache` relies on. The
`/srv/status` should continue to return a success response even if Redis
is down.
Previous to this change our anonymous rate limits acted as a throttle.
New implementation means we now also consider rate limited requests towards
the limit.
This means that if an anonymous user is hammering the server it will not be
able to get any requests through until it subsides with traffic.
This reverts commit e3de45359f.
We need to improve out strategy by adding a cache breaker with this change ... some assets on CDNs and clients may have incorrect CORS headers which can cause stuff to break.
When the server gets overloaded and lots of requests start queuing server
will attempt to shed load by returning 429 errors on background requests.
The client can flag a request as background by setting the header:
`Discourse-Background` to `true`
Out-of-the-box we shed load when the queue time goes above 0.5 seconds.
The only request we shed at the moment is the request to load up a new post
when someone posts to a topic.
We can extend this as we go with a more general pattern on the client.
Previous to this change, rate limiting would "break" the post stream which
would make suggested topics vanish and users would have to scroll the page
to see more posts in the topic.
Server needs this protection for cases where tons of clients are navigated
to a topic and a new post is made. This can lead to a self inflicted denial
of service if enough clients are viewing the topic.
Due to the internal security design of Discourse it is hard for a large
number of clients to share a channel where we would pass the full post body
via the message bus.
It also renames (and deprecates) triggerNewPostInStream to triggerNewPostsInStream
This allows us to load a batch of new posts cleanly, so the controller can
keep track of a backlog
Co-authored-by: Joffrey JAFFEUX <j.jaffeux@gmail.com>
- Define the CSP based on the requested domain / scheme (respecting force_https)
- Update EnforceHostname middleware to allow secondary domains, add specs
- Add URL scheme to anon cache key so that CSP headers are cached correctly
Many security scanners ship invalid mime types, this ensures we return
a very cheap response to the clients and do not log anything.
Previous attempt still re-dispatched the request to get proper error page
but in this specific case we want no error page.
Non UTF-8 user_agent requests were bypassing logging due to PG always
wanting UTF-8 strings.
This adds some conversion to ensure we are always dealing with UTF-8
Previously our custom exception handler was unable to handle situations
where an invalid mime type was sent, resulting in a warning log
This ensures we pretend a request is HTML for the purpose of rendering
the error page if an invalid mime type from a scanner is shipped to the app
This commit introduces 2 features:
1. DISCOURSE_COMPRESS_ANON_CACHE (true|false, default false): this allows
you to optionally compress the anon cache body entries in Redis, can be
useful for high load sites with Redis that lives on a separate server to
to webs
2. DISCOURSE_ANON_CACHE_STORE_THRESHOLD (default 2), only pop entries into
redis if we observe them more than N times. This avoids situations where
a crawler can walk a big pile of topics and store them all in Redis never
to be used. Our default anon cache time for topics is only 60 seconds. Anon
cache is in place to avoid the "slashdot" effect where a single topic is
hit by 100s of people in one minute.
This allows custom plugins such as prometheus exporter to log how many
requests are stored in the anon cache vs used by the anon cache.
This metric allows us to fine tune cache behaviors
This reverts commit 39c31a3d76.
Sorry about this, we have decided againse supporting 0-RTT directly in
core, this can be supported with similar hacks to this commit in a
plugin.
That said, we recommend against using a 0-RTT proxy for the Discourse
app due to inherit risk of replay attacks.
This displays more useful messages for the most common issues we see:
- CSRF (when the user switches browser)
- Invalid IAT (when the server clock is wrong)
- OAuth::Unauthorized for OAuth1 providers, when the credentials are incorrect
This commit also stops earlier for disabled authenticators. Now we stop at the request phase, rather than the callback phase.
The message_bus performs a fair amount of work prior to hijacking requests
this change ensures that if there is a situation where the server is flooded
message_bus will inform client to back off for 30 seconds + random(120 secs)
This back-off is ultra cheap and happens very early in the middleware.
It corrects a situation where a flood to message bus could cause the app
to become unresponsive
MessageBus update is here to ensure message_bus gem properly respects
Retry-After header and status 429.
Under normal state this code should never trigger, to disable raise the
value of DISCOURSE_REJECT_MESSAGE_BUS_QUEUE_SECONDS, default is to tell
message bus to go away if we are queueing for 100ms or longer
